How paranoid are you when it comes to reading old CDs? Well, let's talk to an expert. Bill Orvis, Security Specialist with the U.S. Department of Energy's Computer Incident Advisory Capacity (CIAC) Team, says he could read data from the .16" x 1.25" CD shreddings.

Bill gets right down to the math: "The information on CDs and DVDs are stored as either pits in the plastic (manufactured ones) or as dots of a different color or reflectivity (writable disks)," Orvis said. "These dots can be seen with a good microscope or SEM (scanning electron micrograph), and read. CD tracks are 1.6 microns apart, so this .16" wide piece is 4064 microns wide, which could have 2540 tracks 1.25" long running down it. That's a lot of data."

What does this mean to you? "No one is going to translate the bits on a zillion little pieces to maybe find your credit card number - so for a home based situation, a machine like this is more than adequate. It is also probably adequate for a small business," Orvis said. "For a large business or the government, it is not adequate because access to the data of multi-million dollar projects makes it well worth the time to read all the little pieces. For classified data where people can die if the information gets out, it is inadequate."

The NSA-approved CD shredder that Orvis said he has seen is a grinder that transforms the CD's top surface (where the data resides) into dust, but leaves the rest alone, including the hub where the serial number resides, "so you can be assured that it is properly destroyed," Orvis said.

Orvis suggested this NSA-compliant shredders, for those who have to protect at that level: